WASHINGTON — A peer review of a controversial August federal report on the whereabouts of oil from BP's Deepwater Horizon well upholds its conclusion that three-quarters of the oil had been burned, skimmed or was in the process of degrading, the National Oceanic and Atmospheric Administration said Tuesday.

NOAA Administrator Jane Lubchenco acknowledged that she was wrong in August when she said the original report, which was viewed skeptically by many scientists, had been peer reviewed. The 217-page report released Tuesday was that review, and it validated the initial findings.

Lubchenco said that ongoing studies are under way to reach a conclusion about the oil spill's environmental cost.

"I can't emphasize enough that it doesn't tell us where the oil is today or what its final fate will be or the impact," Lubchenco said.

The initial report was released on Aug. 4, just slightly more than two weeks after BP successfully capped the well, which had gushed an estimated 4.1 million barrels of crude oil in the Gulf of Mexico over 87 days, the largest accidental oil spill ever.

The report was intended to provide a "budget" of what had happened to that oil and to serve as a guide for efforts to clean up oil that could still be recovered.

But it became the immediate target of some scientists who blasted as overly optimistic NOAA's conclusion that the "vast majority of the oil . . . has either evaporated or been burned, skimmed, recovered from the wellhead or dispersed."

The critics said the report implied that much of the oil was gone and no longer posed a risk and questioned how the government scientists had made their calculations. They said the work should have been reviewed by outside experts.

Tuesday's document made few revisions in the original work. "The latest results, by and large, are consistent with early results," the report said.

The lead authors of the report were Bill Lehr of NOAA, Sky Bristol of the U.S. Geological Survey and Antonio Possolo of the National Institute of Standards and Technology. Fifteen other scientists and experts took part in the review, representing universities, consulting groups, ExxonMobil and Canada's environment and fisheries agencies. The University of New Hampshire's Coastal Response Research Center coordinated the review.

The authors' most important change was in the estimate of how much oil had been chemically dispersed. That estimate was revised to 16 percent from 8 percent, though the authors said it could have been anywhere from 10 percent to 29 percent.

Lubchenco said the revision was made on the basis of a better understanding of how dispersants worked below the surface.

The BP blowout was the first time large amounts of chemical dispersants were applied in deep water.

NOAA is coordinating ongoing studies to determine where the oil is now amid reports that some still floats in the Gulf and some has settled into the Gulf's seabed.

Scientific vessels have made 125 sampling expeditions to collect 31,000 water and sediment samples in a broad area of the northern Gulf, but those results haven't been released yet.

The result of that research is more important than where the oil was in August, said Charles Hopkinson, a marine sciences professor at the University of Georgia and the director of the Georgia Sea Grant College Program. Hopkinson was part of a team that did an oil budget that reached different conclusions in August.

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